Using ref cursor vs sys_refcursor inside a Stored Procedure Parameters

CREATE  OR  REPLACE  PROCEDURE GetEmployeesInDept( c OUT  SYS_REFCURSOR)

I am having a query related to the above Stored Procedures, That is while defining the cursor we mentioned it as sys_refcursor, and in some, web site I have seen it as REF CURSOR as shown

create or replace procedure GetEmployeesInDept( c out ref cursor)

Please tell me what is the difference between the ref cursor and sys_refcursor.